Oil-burning process



Dec-.16, 1930. w. SYMMES OIL BURNING PROCESS Filed June 28, 1926 m mu MN um mu \N 1 TTOIUIEYS Patented Dec. 16, 1930 UNITED STATES PATENT, OFFICE.

WHITMAN SYMMES, OF sairrnAivcisoo, cAL'IEoENIA, AssIGivoR 'ro ANSON STILES BLAKE, E BERKELEY, CALIFORNIA OIL-BURNING PROCESS 'A pplication filed June as,

burners are practically noiseless in operation but require a relatively high specific gravity oil, are expensive to manufacture and-their complexity renders them diflicult to install and maintain. The fire pot type I -makesmore or less noise in operation, re-

quires a fairly high specific gravity oil, and does not give a high thermal efficiency comparable with the nozzle type. The nozzle burners inject a spray of oil into the combus- 0 tion chamber of the furnace andcan efliciently burn a high specific gravity oil, are cheap to manufacture and may be quickly put in operation. However the nozzle burners have had one disadvantage in that they are noisy in operation, causing a continuous roar which is very disagreeable in a dwelling. All previous attempts to minimize this noise have failed or have seriously impaired the efficiencyi of the. burner.

It is an object of this invention to devise a process or method of operating a spray nozzle type of oil burner'whereby it will be noiseless in operation and at the same time will have a high thermal eficiency. It is a further object of this invention t devise a practical form of apparatus for carrying out the above process which willbe easy and cheap to install withthe standard forms ofhousehold heating systems.

It is a further object'of this invention to devise an improved arrangement for connecting the oil feed unit to the nozzle burner in which the burner is mounted upon the door of the furnace and is connected to the feed unit by means of one or more flexible tubes or nozzle support pipe and for preventing ac- 1926. Serial No. 118,968..

cumulation of soot on the negative electrode. It is also proposed tosupport the nozzle in such a manner that it'may' be adjusted to direct the spray in any desired direction.

It is a further object 0f,this inventionto provide an oil feed unit in which all leakage from-the pump, compressor, or other apparatus employed is returned to the system.

Another object of this invention is to incorporate an automatic v control means with the furnace for maintaining the draft. through the combustion chamber substantially constant.

Further objects of the invention will appear from the following description in which I have set forth the preferred embodiment of my invention. It is to be understood that the scope of the invention is to bedetermined from the claim and the scopeof the prior art.

Referring to the drawings:

The figure is a side elevational view partly in cross section showing the complete system of this invention.

After much experimentation to determine the cause of the noise produced by the ordinary nozzle' type of burner, I have found that when the burner is being operated within a combustion chamber through which a draft of air is passed, there is a certain critical velocity of the air and products of combustion which if exceeded, causes the flame to burn unevenly and sets up audible vibrations or noise which is transmitted through the furnace walls, piping or conduits to all parts of the building being heated. In this invention the operation of the nozzle is maintained substantially noiseless by maintaining the velocity of the air currents and the prodnets of combustion below this critical velocity, and at the same time providing a suficient quantity of air at a sufiiciently high temperature to eificiently support combustion of all of the oil. In general, the apparatus comprises a combustion chambeiywhich ma be the combustion chamber of any/standard orm of domestic furnace, and which is provided at its bottom with a loose bed of refractory I material, through which substantially all of the air passing into the furnace is forced to pass. The nozzle burner is positioned above v a water jacket 12. It is obvious that the system may be incorporated with any ordinary furnace system whether hot air, steam,

or hot Water. Positioned within the combustion chamber so as to spray oil downwardly into the same, there is a nozzle oil burner designated generally at 13 which receives oil and airunder pressure from the oil feed unit 14.. The side walls of the combustion chamber are at all times substantially closed to ingress of air as it is proposed to introduce all of the air draft through the bottom of the chamber. To form the bottom of the combustion chamber there is provided a loose porous bed 16 of refractory material such as rokenfire brick, which is supported upon the furnace grate 17. For example, with the usual size of household furnace the bed 16 may be four or five inches deep and extend substantially the entire diameter of the combustion chamber, sothat incoming air will be forced to filter through the bed and pass up wardly as a column through the combustion chamber. It is of course understood that air is introduced below the grate 17 either by means of a forced draft arrangement or by opening the ash door 18 or providing an aperture 19 in the same. In the apparatus shown the draft through the combustion chamber is induced by means of. a stack connected to a draft pipe 20. In order to maintain the velocity of the draft substantially constant at all times and independent of the draft produced by the stack there is provided an automatically operated valve designated generally at 21 which will be later described in detail. The nozzle burner 13 comprises generally a mounting 23 which is adapted to be secured to suitable means such as a door 24 of the furnace. This mounting includes a body member 26 which is adapted to be inserted man aperture in the door 24:. The outer end of the body member is provided with a suitable flange which is adapted to be clamped against the outer face of the door 24. The inner portlon of the oil pipe 30 is provided with a goose neck 32 upon the extremity of wh ch s fixed the nozzle spray tip 33. For ign ting the oil spray there is provided a pair of ignition electrodes 34 which are extended through the body member 23, being insulated by means of suitable insulating tubes. The

cone and the inner extremities of the ignition electrodes 34: preferably extend adjacent the periphery of this cone. In order to minimize the formation of soot deposits upon the insulators and upon the electrodes, the body member is fitted with suitably provided upper and lower projections or shelves.

In order to supply current to the ignition electrodes 34:, a suitable high tension transformer is provided which is indicated at 71. The high tension conductors from the transformer are connected to the ignition electrode 3 1 by the flexible conduit 43. Power line connections to both the motor and transformer have been shown as extended through the conduit 72 terminating within the conduit box 73. The current supplied to the motor and transformer may of course be controlled either by means of a manually controlled switch or by means of an automatic thermostat arrangement or by both so that the entire device may be started and stopped merely by controlling the current supplied to the motor and transformer. It may also be convenient to provide an automatic cut-off switch 76 in series with the motor and transformer to arrest operation of the system in case the oil becomes extinguished at the nozzle. Thus as shown in the drawing the cut-off switch 76 is operated by means of oil collected by a drip pan 77 which is positioned directly below the furnace grate 17. The drip pan 77 is connected to the switch 76 by means of a pipe 78 so that if the burner becomes extinguished and the motor continues to operate to eject oil from the nozzle, the oil will drip down thru the fire brick bed 16 and collect in the pan 77 until sufiicient oil has flowed through the pipe 78 to operatev the switch, after which operation of the motor and transformer will be arrested. In order to protect the oil feed unit from dirt and dust, a removable cover 79 may be fitted over the base plate 49.

The automatic damper valve 21 may be of any suitable type which will maintain the draft within the furnace substantially constant and independent of variations in draft in the pipe 20. The particular form of valve shown however, comprises a plate 81 which is curved to form a portion of a cylindrical surface. This plate is pivotally mounted as at 82 near one edge of an open sided housing 83 which is inserted in the draft pipe 20. The edge of the plate is connected to its pivotal axis 82 by means of a pressure plate 84 while the ends of both the plates 81 and 84 nearest the furnace 10 are connected by an end plate 85. The valve is preferably counter balanced by means of a weight 86 connected to the valve by means of a cord 87 which is wrapped about the outer surface of the curved plate 81. With this form of valve the plate 84 always presents a constant pressurearea plate 81 will rotate inward to a certain angle to permit a certain amount of external air to enter the open housing 83. If the draft increases from some cause then the plate 81 will rotate farther into the housing to admit more air to the draft pipe and conversely if the draft decreases the plate will rotate to a position farther out from the housing to restrict passage .of air into the pipe 23. Thus the effect of this valve is to maintain substantially a constant draft in the furnace independent of variation of draft in the pipe 20. The value of the draft within the furnace may be varied by changing the mass of the counterweight 86.

To install this system with a standard domestic furnace it is not necessary to make extensive alterations. The combustion chamber 11 may be left undisturbed and the bed 16 of broken fire-brick may be placed directly upon the furnace grate. The nozzle burner 13 may be readily mounted upon the furnace door and the nozzle 13 adjusted by bending the goose neck or by adjusting the pipe 30 in its mounting until the oil spray is in the desired direction. The oil feed unit 14 may be placed in a convenient position beside the furnace 10, and because of the manner in which the connections have been made to the motor and cut out switch 76 it is only necessary to connect the line conduit 72. Because of the flexible connections between the nozzle and the feed unit 14 the furnace door 24 may be swung partly open to inspect and adjust the burner when in operation. The use of flexible connections between the nozzle and feed unit is an important feature of my invention since it not only makes possible the mounting of the pump and compressor at a safe distance from the furnace but it also obviates the use of pipe joints adjacent the furnace which are apt to leak.

In operating the system, upon closing the circuit to the motor and transformer a mixture of oil and air is sprayed from the nozzle 33 above the fire brick bed 16. The spark discharge across the end of the electrode 34 will ignite the spray and by adjusting the .1 nozzle either by bending the goose neck 34 or by shifting the pipe 30 in the burner mounting, the burner flame may be projected downwardly toward the center of the combustion chamber. The pressure of the oil and the character of the nozzle are preferably such that the flame produced will be what is commonly termed a slow or lazy flame which preferably should be adjusted so that the flame is not impinged upon the walls of the furnace. Good results have been obtained by using a Diesel oil of 24 to 28 degrees Baum sprayed at a pressure of from 4 to 9 pounds per square inch. By the use of fire-brick bed 16 the draft entering the mmbustion chamber may be maintained substantially uniform in velocity, that is the velocity of the draft at all points in a plane taken parallel to the surface of the bed 16 will be substantially constant. Furthermore, by proper regulation of the automatic damper valve 21 the velocity of the air within the combustion chamber and the velocity of the products of combustion are maintained below the critical value which cause the flame to produce sound. Heating of the bed 16 will also cause the draft entering the chamber to be preheated to a uniform temperature. With this arrangement the burner when properly adjusted is practically noiseless and cannot be heard even when standing only a few feet away from the furnace. Furthermore, the thermal efliciency of the system is very high and the flame occurs without formation of soot.

I claim:

A noiseless method of burning oil utilizing a nozzle for spraying the oil, a combustion chamber, and a porous bed of loose material forming the lower wall of the combustion chamber, said method comprising inducing a draft of air upwardly through said bed, spraying oil downwardly toward said bed to maintain combustion within the chamber, and maintaining the pressure within the chamber substantially constant.

In testimony whereof, I have hereunto set my hand.

WHITMAN SYMMES. 

